Which of the following are NOT valid variables to be examined using a scatterplot and why? Car price, car size, and car color cannot be displayed using a scatterplot because only a maximum of two variables can be explored using a scatterplot. Life expectancy, population size, and country GDP cannot be displayed using a scatterplot because only a maximum of two variables can be explored using a scatterplot. Life expectancy, population size, and country GDP cannot be displayed because GDP is categorical. Car price, car size, and car color cannot be displayed using a scatterplot because car color is categorical